MSD trouble 468 BBC
Broke in the rebuilt 468 BBC motor this weekend getting ready for CFW. MSD 6m ignition, msd dist., msd coil. Electric tach hooked to the msd box became erratic and then the motor quit. Started again and went 100 feet, exact sequence happened. Got towed in. Any ideas ? It seemed that the tach goes wild and the seconds later the motor quits. Need to get this figured out before friday, 3 days planned at CFW Fathers Day.
Have you tried running it with the tach disconnected?
Also, double, then triple check every single connection on the system. The ground, both hot leads. Then re check what the ground path is. Is the box ground on the block and the battery gorund on the rail? Or maybe reverse of that. The box ground should be on the same piece that the battery gorund is hooked to.
Anodized alum sucks as a ground source.
LINK:GN-RACING.COM
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As bob said check that you have a good ground. I ground mine to the block but every time i disconnect the ground i re-hit that area as well as the back of the connector with some 80grit sandpaper before reconnecting it!
Those box's do some funny shit when presented with low voltage too, curious, does the problem happen to start once your on the gas?
If you dont have the manual go on line and down load it. Its has a trouble shooting section in the back. If you cant find the problem there call MSD I beleive they are in El Paso Tx. They are a lot of help. Their product, They will know and they have always helped me. Great tech support.
BTW there will be a munaul for the distributor and a manual for the controll box. If all else fails you can get a DUI for about the same price as the marine version of the controll box. Boat #2 has a marine DUI on it.
Last edited by md-11mike; 06-03-2012 at 08:46 PM.
Found 1 loose wire, maybe fixed
Went thru all of the connections. Cleaned all grounding connections. Found 1 loose wire on a lug off the dead man switch, it came uncrimped. I could pull it out of the lug. Hopefully this is the problem as if the wire pulled a little out while running the ignition would quit.
The question is if the wire was barely connected could the tach act up a little before the engine quit ? The engine quit maybe 30 seconds after the tach went wild the first time and the tach went wild and the engine quit immediately the second time.
I guess the only way to prove it is fixed s to get on the lake, don't want to be towed again if it quits again. It runs fine on the trailer, ran it for several minutes with water but any longer and the headers get really hot without water.
Going to CFW next week, lots of tow boats but want it to run without any problems this year.
Like i said those MSD box's will do some weird shit! On my deal I run separate on/off switches for fuel and ignition and one time while out I accidently flipped off the ignition switch realized it and flipped it back on (this happened very quickly). All of a sudden the engine started missing bad and running like shit, i shut it down, gave it a few seconds, lite it back up and everything was normal. I wouldn't doubt that if your problem could be that loose ignition wire!
Yeah, a loose wire like that could reasonably cause problems with the tach; as the boat jostles around the box is getting voltage, not getting voltage, getting voltage, etc. The boxes don't have to "boot" or anything like that, but that does cause a lot of power surges within them (lots of capacitors and inductors that can oscillate) that will make a very confused output signal.Originally Posted by infotraker
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